Methods and apparatus for providing self-contained guidance, navigation, and control (GN&C) functions for a vehicle moving through an environment on or near the ground, in the air or in space without externally provided information are disclosed. More particularly, one embodiment of the present invention includes a Heading Sensor (36), an Absolute Location Sensor (38), a timer (40), a Range Doppler Processor (42), a Navigation Reference Sensor (44), an Area Range and a Velocity Sensor (46) which provide enhanced navigation information about a universal reference frame (22) and one or more targets (20).

A hyperbolic waveform multiple-input multiple-output radar includes a generator circuit, multiple transmit circuits, a multiple-input multiple-output antenna, and multiple receive circuits. The generator circuit may be operable to generate a linear frequency modulated signal and a hyperbolic frequency modulated signal. The transmit circuits may be operable to generate multiple transmit signals by analog mixing the linear frequency modulated signal and the hyperbolic frequency modulated signal in response to a plurality of coding family parameters, wherein the transmit signals define an orthogonal family of waveforms. The multiple-input multiple-output antenna may be operable to transmit the transmit signals toward an object and receive multiple receive signals from the object. The receive circuits may be operable to determine multiple data signals in response to the receive signals, wherein the data signals are suitable to determine a distance between the multiple-input multiple-output antenna and the object.

A hyperbolic waveform multiple-input multiple-output radar includes a generator circuit, multiple transmit circuits, a multiple-input multiple-output antenna, and multiple receive circuits. The generator circuit may be operable to generate a linear frequency modulated signal and a hyperbolic frequency modulated signal. The transmit circuits may be operable to generate multiple transmit signals by analog mixing the linear frequency modulated signal and the hyperbolic frequency modulated signal in response to a plurality of coding family parameters, wherein the transmit signals define an orthogonal family of waveforms. The multiple-input multiple-output antenna may be operable to transmit the transmit signals toward an object and receive multiple receive signals from the object. The receive circuits may be operable to determine multiple data signals in response to the receive signals, wherein the data signals are suitable to determine a distance between the multiple-input multiple-output antenna and the object.

An enhanced Long Range Navigation (eLORAN) system may include an eLORAN controller configured to obtain satellite-derived conductivity data and satellite-derived temperature data for different geographical positions and generate eLORAN correction factors based thereon. The eLORAN system may also include eLORAN transmitter stations. The eLORAN system may also include an eLORAN receiver device that may include an eLORAN receive antenna and an eLORAN receiver coupled to the eLORAN receive antenna and configured to receive the eLORAN correction factors. The eLORAN receiver device may also include a controller coupled to the eLORAN receiver. The controller may be configured to cooperate with the eLORAN transmitter stations to determine an eLORAN receiver position corrected based upon the eLORAN correction factors.

An enhanced Long Range Navigation (eLORAN) system may include an eLORAN controller configured to obtain satellite-derived conductivity data and satellite-derived temperature data for different geographical positions and generate eLORAN correction factors based thereon. The eLORAN system may also include eLORAN transmitter stations. The eLORAN system may also include an eLORAN receiver device that may include an eLORAN receive antenna and an eLORAN receiver coupled to the eLORAN receive antenna and configured to receive the eLORAN correction factors. The eLORAN receiver device may also include a controller coupled to the eLORAN receiver. The controller may be configured to cooperate with the eLORAN transmitter stations to determine an eLORAN receiver position corrected based upon the eLORAN correction factors.

Apparatus and methods are presented for synchronising a slave device signal to a reference timebase, in situations where the slave device lacks knowledge of the propagation delay for signals from the reference device, e.g. if the positions of one or both of the devices are unknown or classified, or the inter-device signal propagation distance is otherwise a-priori unknown. Reference signal propagation delay is determined using an exchange of signals between the devices, with each device using a differencing procedure for eliminating effects of receiver line bias and other hardware delays. In another aspect an exchange of signals between the devices is used to detect a time residual arising from an inaccurate propagation delay estimate. The synchronisation methods can be applied to a plurality of slave devices for providing a synchronised location network. In certain embodiments signals are transmitted wirelessly, while in other embodiments they are transmitted via a fixed line.

Apparatus and methods are presented for synchronising a slave device signal to a reference timebase, in situations where the slave device lacks knowledge of the propagation delay for signals from the reference device, e.g. if the positions of one or both of the devices are unknown or classified, or the inter-device signal propagation distance is otherwise a-priori unknown. Reference signal propagation delay is determined using an exchange of signals between the devices, with each device using a differencing procedure for eliminating effects of receiver line bias and other hardware delays. In another aspect an exchange of signals between the devices is used to detect a time residual arising from an inaccurate propagation delay estimate. The synchronisation methods can be applied to a plurality of slave devices for providing a synchronised location network. In certain embodiments signals are transmitted wirelessly, while in other embodiments they are transmitted via a fixed line.

The present invention proposed a weighted Centroid Localisation (WCL) algorithm, which does the location estimation based on the known positions of the gateways and the measurements times of arrival (TOA) at the gateways. The algorithm computes the weight of the gateway based on their rank when the gateways are sorted by their TOA. Simulations have demonstrated the algorithm's robustness under different multipath/fading channel conditions and its good location performance.

The present invention proposed a weighted Centroid Localisation (WCL) algorithm, which does the location estimation based on the known positions of the gateways and the measurements times of arrival (TOA) at the gateways. The algorithm computes the weight of the gateway based on their rank when the gateways are sorted by their TOA. Simulations have demonstrated the algorithm's robustness under different multipath/fading channel conditions and its good location performance.

An eLORAN receiver may include an antenna and eLORAN receiver circuitry coupled to the antenna. The antenna may have a ferromagnetic core including a ferromagnetic medial portion and ferromagnetic arms extending outwardly from the ferromagnetic medial portion, a respective electrically conductive winding surrounding each of the ferromagnetic arms, and an electrically conductive patch element adjacent the ferromagnetic core.